High voltage electric circuit breaker with means for precisely coordinating the operation of widely spaced components



Oct. 31, 1967 P. E. BADEY ET AL 3,350,519 HIGH VOLTAGE ELECTRIC CIRCUIT BREAKER WITH MEANS FOR PRECISELY COORDINATING THE OPERATION OF WIDELY SPACED COMPONENTS Filed Dec. 30, 1965 2 Sheets-Sheet 1 //VVE/VTO/?S.'- PA UL E BADEY, JOHN A. OPPEL,

Oct. 31, 1967 P. E. BADEY ET AL 3,350,519 HIGH VOLTAGE ELECTRIC CIRCUIT BREAKER WITH MEANS FOR PRECISELY COORDINATING THE OPERATION OF WIDELY SPACED COMPONENTS Filed Dec. 30, 1965 .2 Sheets-Sheet 2 Flgfi.

/4 I /a a w VII/I114 wmI/ I 770 I 7 0 2 60a 62 O A9 A9 INVENTORS.

PA 01. E. 5,405), JOHN A. OPPEL,

ATTORNEY United States Patent and John A. Oppel, Electric Company, a

ABSTRACT OF THE DISCLOSURE A high voltage electric circuit breaker comprising a pair of widely-spaced supporting pads, a pair of substantially simultaneously operable circuit controlling assemblies mounted on said pads, each of said assemblies comprising a movable contact and a linkage for controlling motion of said contact, a common base extending between said pads, pivotal control members mounted on said base, a link mechanically interconnecting said con trol members, said base and said link being of such materials that in response to a given temperature change, the length of said base between said pivots changes by an amount substantially equal to the change in length of said link and in the same direction.

This invention relates to a high voltage electric circuit breaker of the type comprising a plurality of widely spaced circuit-controlling assemblies that are mechanically coupled together to provide for precise coordination of the operation of the assemblies.

In the high voltage circuit breaker that we are concerned with, there are a plurality of circuit-controlling assemblies which are respectively mounted on individual supporting pads. These supporting pads are widely spaced apart in order to provide the necessary electrical clearance between the live parts of the circuit-controlling assemblies. The operation of the circuit-controlling assemblies is coordinated by means of an interconnecting link mechanically connecting together the control linkages of the individual assemblies. Because of the relatively great spacing between the supporting pads, this link is of a relatively great length.

A problem that has arisen in prior circuit breakers of this type is that the desired coordination between the circuit-controlling assemblies is subject to being upset by ambient temperature changes. In this regard, a large change in ambient temperature will produce a relatively great change in the length of the long interconnecting link between the control linkages of the two assemblies. This tends to shift the position of one control linkage relative to the other, thus upsetting any preadjusted positional relationship between the two control linkages.

Another problem in such circuit breakers is that the desired coordination between the circuit-controlling assemblies can be upset by a change in the spacing between the supporting pads, as might result from unequal settling of the pads in the surrounding earth. Such a change in pad-spacing, while the interconnecting link remains coupled between the two control linkages, can shift one linkage relative to the other, thus disturbing any preadjusted positional relationship between the two linkages.

An object of our invention is to construct the circuit breaker in such a manner that the desired coordination between the widely spaced circuit-controlling assemblies is not upset by large ambient temperature changes, which change the length of the connecting link, or by substantial variations in the spacing between the supporting pads.

In carrying out our invention in one form, we provide an electric circuit breaker that comprises a pair of Widely spaced supporting pads and a pair of substantially simultaneously operable circuit-controlling assemblies respectively mounted on the pads. Each circuit-controlling assembly comprises a movable contact and a linkage for controlling its motion. Each of the linkages comprises a pivotally mounted control member and a pivot for mounting the control member for pivotal motion. A common base extends between these pads and the two pivots are mounted on this common base. The common base is fixed to one of the pads and is mounted on the other of the pads in a manner that permits relative movement of the base relative to said other pad. A link mechanically interconnects the control members to cause the control members to move in unison during circuit breaker operation. The base and the link are of such materials that, in response to a given ambient temperature change, the length of the base between said pivots changes by an amount substantially equal to the change in length of the link and in substantially the same direction.

For a better understanding of the invention, reference may be had to the following description taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a side elevational view schematically illustrating one form of the invention.

FIG. 2 is a schematic showing, principally a wiring diagram, illustrating one of the circuit-controlling assemblies constituting the circuit breaker of our invention.

FIG. 3 is an enlarged view illustrating the behavior of certain parts of the circuit breaker when constructed as in the prior art.

FIG. 4 is a view similar to FIG. 2 but illustrating the behavior of these parts when constructed in accordance with our invention.

FIG. 5 is a sectional view taken along the line 5-5 of FIG. 1.

FIG. 6 is a sectional view illustrating a modified form of the invention.

Referring now to FIG. 1, the circuit breaker shown therein comprises a pair of circuit-controlling assemblies 12 and 14, each of which is mounted on its individual supporting pad 15. Each of the supporting pads 15 comprises a massive block 19 of concrete deeply imbedded in the surrounding earth 16 and a rigid metal framework 18 fixed to the top of concrete block 19. Each circuitpad 15.

In one embodiment of our trolling assemblies 12 and phases of a high voltage these phases are at widely invention, the circuit-con- 14 are the pole units in two polyphase A-C circuit. Since Each of the circuit-controlling assemblies 12 and 14 is preferably constructed in the manner disclosed and matic form. In the schematic showing of FIG. 2, a wiring diagram is provided to circuit-controlling assembly 12 or 14 that are located within the high voltage metal tank 20. More specifically, disposed within the tank 20 are two seriallyconnected pairs 22 and 24 of relatively movable main contacts. Each pair of main contacts comprises a stationary contact 25 and a movable contact 26. The two stationary contacts are supported on terminal bushings 28 projecting through opposite ends of the metal tank 20. These bushings 28 comprise conductive studs 29 for carrying current to and from the stationary contacts 25 and insulators 36 for insulating the conductors 29 and the stationary contacts 25 from the tank 20 when the circuit breaker is open, as shown in FIG. 2.

Shunting each pair of main contacts in FIG. 2 is the series combination of a resistor 32 and a resistor switch 34. The resistor switch 34 comprises a stationary contact 36 and a movable contact 37. The resistor 32, when connected across the main contacts 22 and 24, serves to control the rate of voltage build-up across the main contacts during a circuit-opening operation and also to control the magnitude of the voltage transient developed when the circuit breaker is closed. For performing this latter control function, each resistor switch 34 must be closed slightly ahead of the main contacts which it shunts. In addition, the resistor switches in the different phases of the polyphase A-C circuit must be closed substantially simultaneously in order to limit the magnitude of the voltage transient developed upon circuit-breaker closing. In this latter respect, it is required in certain circuit breakers that the resistor switches in the different phases make contact within 2.77 milliseconds of each other during a closing operation. This present invention is concerned with means for providing this precise coordination, and such means will soon be described in detail.

In FIG. 1, one resistor switch 34 is shown in the circuitcontrolling assembly 12 of one phase, and an identical resistor switch 34a is shown in the circuit-controlling assembly of the adjacent phase. Each of these resistor switches comprises a stationary contact 36 and a movable bridging contact 37 corresponding to the similarly designated contacts of FIG. 2. In each switch, the stationary contact 36 is connected to one end of the resistor and is supported on a suitble insulator 39 electrically insulating it from the tank 20 when the switch is open. The movable contact 37 is mounted on a contact-carrying arm 38 that is pivotally supported on the tank 20 by a stationary pivot 46. In the illustrated embodiment, the movable contact 37 has a mounting rod 41 connected to its back surface. This mounting rod 41 extends through a hole in the contact-carrying arm 38 and is slidably mounted in this hole. A compression-type wipe spring 42 urges the movable contact 37 toward the other contact 36, but an adjustable stop 43 on the back end of the rod 41 limits the extent of such movement. A suitable flexible conductor (not shown) is provided for carrying current between the contact 37 and its carrying arm 38.

In each of the tanks 20 there is a compression-type closing spring 44 for biasing the movable contact-carrying arms 38 in a counterclockwise direction toward a closed position where contacts 36 and 37 engage. This compression spring 44 acts through the upper end of a vertically extending rod 46 of insulating material that is suitably coupled to the contact carrying arm 38 of the switch. For holding both of the resistor switches 34 and 34a in their fully-open position of FIG. 1, a closing control latch 50 is provided at the bottom of the right-hand insulating column 17. This closing-control latch 50 acts to hold each of the vertically-extending insulating rods 46 in its depressed postion against the upward bias of closing spring 44. But when the latch 50 is released, the rods 46 are free to move upwardly, and the closing springs 44 can therefore expand to drive their associated contacts 37 through a closing stroke.

To assure that the contact-carrying arms 38 of the two switches 34 and 34a will move in unison through their 4 respective closing strokes, the two contact-carrying arms 38 are mechanically tied together. This mechanical tie is provided by means of a tie link 60 extending between the two circuit-controlling assemblies 12 and 14 at the base of columns 17. This link 60 is connected at its left hand end to a control linkage of assembly 12 and at its right hand end to a corresponding control linkage of assembly 14.

The control linkage for circuit-controlling assembly 12 comprises a bell crank 62 mounted on a generally stationary pivot 63. One arm of this bell crank 62 is pivotally connected to the link 60 by means of a pivot 64; and the other arm is pivotally connected at 65 to a forcetransmitting element in the form of a universal link 68, which, in turn, is connected to the lower end of the vertical rod 46. The connection between the universal link 68 and the rod 46 is preferably a universal joint 69. A suitable guide 76 is provided in the column 17 to confine movement of the rod 46 to a substantially vertical path.

In a slightly modified form of our invention (not shown), we omit the universal link 68 and provide the rod 46 with an integral extension that is directly connected to the crank 62 by means of pivot 65. The verticallyextending rod 46 is so long that a slight amount of hori zontal movement at its lower end produces no significant vertical motion at its upper end. Whether or not a universal link is used, the force-transmitting element that is connected to the crank 62 is mounted for movement at the upper end in a direction generally perpendicular to the path followed by pivot 63 during movement base in response to thermal expansion.

The control linkage of the circuit-controlling assembly 14 corresponds in most respects to that of the assembly 12, and corresponding parts of the two control linkages have therefore been assigned similar reference numerals. The bell crank 62 of the right hand assembly differs from that of the left hand assembly, however, by having on its lower arm an extension that carries a latching roller 72. When the circuit breaker is open as shown in FIG. 1, the previously-described closing control latch 50 cooperates with this roller 72, preventing the bell cranks 62 from moving clockwise from their illustrated positions under the bias of closing springs 44.

The closing-control latch 50 is mounted on a stationary pivot 75 and is biased into its latching position illustrated by means of a reset spring 76. For operating the latch 50 to its unlatched position, a solenoid schematically shown at 78 is provided. When solenoid 78 is energized, it lifts its armature, thereby driving latch 50 clockwise about its pivot 75 to release the latching roller 72 and crank 62. Closing springs 44 then become effective to drive contactcarrying arms 38 into their closed position.

To assure that the movable contacts 37 engage their respective stationary contacts 36 at substantially the same instant, the adjustable stops 43 on the contacts 37 are relied upon. By suitably adjusting these stops 43 when the switches are in their open position, the open-circuit spacing between the contacts 37 and 36 of each switch can be changed, thereby changing the instant at which the contacts 37 and 36 will engage upon closing.

A problem that has arisen in circuit breakers of the general type shown is that the above-described adjustment between the contacts 37 has been susceptible to being upset by ambient temperature variations. The expansion or contraction produced by such temperature variations will produce an appreciable change in the length of tie link 60 in view of its great length. Assuming that the two pivots 63 for the bell crank 62 are stationary, such changes in the length of link 60 will cause appreciable rotation of the left hand crank 62 while the right hand crank 62 remains latched'in its position shown. This rotation of the left hand crank will appreciably change the position of the contact-carrying arm 38 in the assembly 12.

This behavior is illustrated in FIG. 3, where the pivot 63 of crank 62 is assumed to remain fixed and the tie link.

60 is assumed to increase its length by an amount D. This increase in length rotates the crank 62 into the illustrated dotted line positon, moving the link 68 and the control 46 upwardly by an amount E. This upward movement E of the control rod 46 would, of course, appreciably decrease the preadjusted spacing between the contacts 37 and 36. As a result, during a subsequent closing operation, the contact 37 of assembly 12 would reach its closed position appreciably ahead of the contact 37 of the other assembly 14, thus defeating the precise preadjustment that had been made with the aim of producing simultaneous contact-make.

To prevent the control rod 46 from moving upwardly a significant distance in response to such changes in the length of link 60, we mount the pivot 63 for crank 62 in such a manner that its position shifts by substantially the same distance as the link 60 changes in length and in substantially the same direction. This is illustrated in FIG. 4 where the pivot 63 shifts to the left through a distance F substantially equal to the increase in length D of the link 60. This will produce a very slight vertical movement of the pivot 69 by an amount E, but this amount E is much smaller than the amount E in FIG. 3 and is not large enough to be significant. In effect, the relative angular positions of the two cranks remain substantially fixed with respect to each other despite a change in the length of link 60.

For producing this compensating shift F in the position of pivot 63, we mount the pivots 63 for the two cranks 62 on a common base 80 that is made of the same material as the tie link 60. In a preferred form of the invention, both the base 80 and the tie link 60 are made of steel. This base 80 is supported on both of the frame works 18 that support the two circuit-controlling assemblies 12 and 14. But the base 80 is rigidly secured to the right-hand framework 18, while it is slidably mounted on the left-hand framework 18 so that it is free to shift longitudinally of itself with respect to the left-hand framework 18. Since the base 80 is of the same material as the link 60, a given change in ambient temperature pro duces substantially the same change in the length of base 80 as the change in the length of link 60, both changes in length being in the same direction.

The slidable mounting of the base 80 on the left-hand framework 18 of FIG. 1 can be provided in any suitable manner. In the illustrated embodiment of the invention, an opening 82 is provided in the left-hand framework 18 and the base 80 is slidably received in this opening. This allows the base 80 to slide within the opening in response to thermal expansion or contraction longitudinally thereof. The closely-surrounding walls of the opening 82 serve to guide the base 80 as its length changes. At its opposite end, the base 80 is fixed to the right-hand framework 18 by suitable means, such as bolts 84 extending through the top of the framework 18 and base 80 and clamping these parts together. The base 80 can be of any suitable form, but we prefer to construct it as an enclosure of hollow rectangular cross-section (FIG. 5) that generally surrounds the tie link 60.

It is recognized that a change in temperature will produce a small change in the length of the vertically-extending control rods 46. But this change in length does not significantly affect the relative positions of the two contact-carrying arms 38 with respect to each other be cause the two control rods 46 are of substantially the same material and length. Hence, their length changes by substantially the same amount in response to a given temperature change, thus displacing the contact-carrying arms 38 by substantially the same amount.

As mentioned hereinabove, another object of the invention is to prevent any disturbance in the coordination between the widely spaced circuit-controlling assemblies as a result of a change in the spacing between pads 15. The posi bility exists that the pads will shift slightly with respect to each other as a result of settlement or frost conditions affecting the soil 16. If the pivots 63 of the two cranks were fixed to the two pads 15 or to the framework portions 18 of the two pads, any shifting of the pads that changed the spacing therebetween would cause a corresponding pivoting of the crank 62 of the left hand assembly 12. No such pivoting of this crank 62 occurs with our arrangement because the left hand pad 15 can shift with respect to the right hand pad without alfecting the spacing between the pivots 63. In this respect, the sliding joint at 82 on the left hand pad allows the left hand pad to shift without changing the distance between pivots 63. Since this spacing remains unchanged and the length of the link 60 also remains unchanged despite such shifting of pads 15, the angular position of the left hand crank 62 remains unchanged. Thus, the change in spacing between the pads produces no significant change in the relative positions of the two contact-carrying arms 38 of the assembies 12 and 14.

assemblies (12 and 14),

equally well be applied to a circuit breaker that comprises a greater number of such assemblies. For example, in FIG. 6, a 3-phase circuit breaker is shown. This circuit breaker comprises a third asembly 90 for controlling the third phase of the power circuit. This asembly 90 is located in a position to the right of the assembly 14, so that the assembly 14 is centrally located. This third assembly 90 is substantially identical to the assembly 12 in FIG. 1. It comprises a substantially identical control linkage comprising a crank 62 tied to the central crank 62 of assembly 14 by means of a tie link 60a corresponding to 60 of FIG. 1. This tie link 69a is preferably coupled to an extension 100 of the central crank 62 by means of a pivotal connection 101.

In applying our invention to such a circuit breaker, we extend the base over to the supporting pad 15 of the third assembly 90, slidably supporting the base on this pad of the third assembly, as shown at 82.

The pivot of crank 62 in the third assembly is mounted on base 80 and thus is movable with the base 80 when it expands and contracts in response to temperature changes. This compensates for thermally-induced changes in the length of link 60 in the same manner as described with respect to FIG. 1.

While we have shown and described bo iments of our fall within the true spirit and scope of our invention.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. An electric breaker comprising:

(a) a pair of widely-spaced supporting pads,

(b) a pair of substantially simultaneously operable circuit-controlling assemblies respectively mounted on said pads.

(c) each circuit-controlling assembly comprising a movable contact and a linkage for controlling motion of said movable contact,

((1) each of said linkages mounted control member,

(e) a pair of pivots respectively mounting said control member for pivotal motion,

(f) a common base extending between said pads on which said pivots are supported,

(g) means for fixing said base to one of said pads,

(h) means for mounting said base on the other of said pads in a manner that permits relative movement of said base relative to said other pad,

(i) a link mechanically interconnecting said control members to cause said control members to move in unison during circuit breaker operation,

(j) said base and said link being of such materials comprising a pivotallythat in response to a given temperature change, the length of said base between said pivots changes by an amount substantially equal to the change in length of said link and in substantially the same direction. 2. The circuit breaker of claim 1 in which said base and said link are constructed of materials that have substantially the same coefficient of thermal expansion.

3. An electric circuit breaker comprising:

(a) a pair of Widely-spaced supporting pads,

(b) a pair of substantially simultaneously operable circuit-controlling assemblies respectively mounted on said pads,

(c) each circuit controlling assembly comprising a movable contact and a linkage for controlling motion of said movable contact,

((1) each of said linkages comprising a pivotallymounted control member,

(e) means for maintaining the angular positions of said control members substantially fixed with respect to each other despite thermal expansion or contraction of said link, comp-rising:

(i) a common base extending between said pads,

(ii) means for supporting said pivots on said common base,

(iii)means for fixing said base to one of said pads,

(iv) means for mounting said base on the other of said pads for relative movement with respect to said other pads,

(v) said base and said link being of such materials that in response to a given temperature change the length of said base between said pivots changes by an amount substantially equal to the change in length of said link and in substantially the same direction.

4. The circuit breaker of claim 3 in which said base and said link are of materials that have substantially the same coefficient of thermal expansion.

5. The circuit breaker of claim 3 in which the control linkage for the assembly that has the base movably mounted on its pad comprises a force-transmitting element that has one end pivotaly connected to said pivotally mounted control member and its opposite end mounted for movement in a path extending generally perpendicular to the path followed by the pivot of said control member during movement of said pivot in response to thermal expansion of said base.

.6. The circuit breaker of claim 1 in which each of said circuit-controlling assemblies comprises a main break and a resistor shunting said main break, said movable contacts of claim 1 being respectively connected in series with said resistors to control the flow of current therethrough.

References Cited FOREIGN PATENTS 348,555 5/1931 Great Britain. ROBERT K. SCHAEFER, Primary Examiner.

H. BURKS, Assistant Examiner. 

1. AN ELECTRIC BREAKER COMPRISING: (A) A PAIR OF WIDELY-SPACED SUPPORTING PADS, (B) A PAIR OF SUBSTANTIALLY SIMULTANEOUSLY OPERABLE CIRCUIT-CONTROLLING ASSEMBLIES RESPECTIVELY MOUNTED ON SAID PADS, (C) EACH CIRCUIT-CONTROLLING ASSEMBLY COMPRISING A MOVABLE CONTACT AND A LINKAGE FOR CONTROLLING MOTION OF SAID MOVABLE CONTACT, (D) EACH OF SAID LINKAGES COMPRISING A PIVOTALLYMOUNTED CONTROL MEMBER, (E) A PAIR OF PIVOTS RESPECTIVELY MOUNTING SAID CONTROL MEMBER FOR PIVOTAL MOTION, (F) A COMMON BASE EXTENDING BETWEEN SAID PADS ON WHICH SAID PIVOTS ARE SUPPORTED, (G) MEANS FOR FIXING SAID BASE TO ONE OF SAID PADS, (H) MEANS FOR MONTING SAID BASE ON THE OTHER OF SAID PADS IN A MANNER THAT PERMITS RELATIVE MOVEMENT OF SAID BASE RELATIVE OT SAID OTHER PAD, (I) A LINK MECHANICALLY INTERCONNECTING SAID CONTROL MEMBERS TO CAUSE SAID CONTROL MEMBERS TO MOVE IN UNISON DURING CIRCUIT BREAKER OPERATION, (J) SAID BASE AND SAID LINK BEING OF SUCH MATERIALS THAT IN RESPONSE TO A GIVEN TEMPERATURE CHANGE, THE LENGTH OF SAID BASE BETWEEN SAID PIVOTS CHANGES BY AN AMOUNT SUBSTANTIALLY EQUAL TO THE CHANGE IN LENGTH OF SAID LINK AND IN SUBSTANTIALLY THE SAME DIRECTION. 